1. Field
Example embodiments relate to a method of compensating for distortion of an exposure pattern due to stage yawing in a maskless exposure apparatus using digital micromirror devices (DMDs).
2. Description of the Related Art
Generally, a pattern may be formed on a substrate constituting a liquid crystal display (LCD), a plasma display panel (PDP) and/or a flat panel display (FPD) by applying a pattern material to the substrate and selectively exposing the pattern material using a photomask to selectively remove the portion of the pattern material whose chemical properties have been changed or the remaining portion of the pattern material.
With the increase in size of a substrate and the precision of a pattern, a maskless exposure apparatus that forms a pattern on the substrate without using a photomask is under development. The maskless exposure apparatus forms a pattern by transferring light beams to the substrate according to pattern information created by an electric signal from an electronic device, for example, a digital micromirror device (DMD). The DMD includes a plurality of micro minors by which incident light having given angles is transmitted with desired angles, and other light is transmitted with other angles, thereby exposing a pattern on an exposed surface using the selected light.
The maskless exposure apparatus using the DMD changes a DMD image (frame) at predetermined/desired intervals, when a stage to move the substrate is scanned in an exposure direction at predetermined/desired speed, to expose the pattern on the exposed surface. At this time, the predetermined/desired intervals are maintained through synchronization with pulses generated at predetermined/desired intervals by a timer of the stage. The position of the stage, referred to as a position event generator (PEG, hereinafter referred to as a sync signal), is generally used. In the maskless exposure apparatus, however, exposure continuously occurs during scanning, with the result that distortion of an exposure pattern due to stage yawing occurs, which directly affects exposure quality. Particular with the development of technology, the size of the substrate has gradually increased, and therefore, the size of the stage has increased. As a result, stage yawing becomes more severe. Conventional methods of minimizing such stage yawing have been proposed; however, minimizing the yawing is limited when the stage is large.